[libcamera-devel,v2,1/3] libcamera: Add support for monochrome sensors

12649 diff mbox series

This commit adds support for monochrome (greyscale) raw sensors. These
are sensors that have no colour filter array, so all pixels are the
same and there are no distinct colour channels.

These sensors still require many of an ISP's processing stages, such
as denoise, tone mapping, but not those that involve colours (such as
demosaic, or colour matrices).

Signed-off-by: David Plowman <david.plowman@raspberrypi.com>
---
 include/libcamera/internal/bayer_format.h |  3 ++-
 src/libcamera/bayer_format.cpp            | 14 ++++++++++++--
 src/libcamera/camera_sensor.cpp           |  3 +++
 src/libcamera/property_ids.yaml           |  4 ++++
 4 files changed, 21 insertions(+), 3 deletions(-)

Hi David,

On 18/06/2021 17:18, David Plowman wrote:
> This commit adds support for monochrome (greyscale) raw sensors. These
> are sensors that have no colour filter array, so all pixels are the
> same and there are no distinct colour channels.
> 
> These sensors still require many of an ISP's processing stages, such
> as denoise, tone mapping, but not those that involve colours (such as
> demosaic, or colour matrices).


Aha, I was wondering why we needed a bayer format if it wasn't a bayer
pattern - but it's about continuity in the processing pipeline.

> Signed-off-by: David Plowman <david.plowman@raspberrypi.com>
> ---
>  include/libcamera/internal/bayer_format.h |  3 ++-
>  src/libcamera/bayer_format.cpp            | 14 ++++++++++++--
>  src/libcamera/camera_sensor.cpp           |  3 +++
>  src/libcamera/property_ids.yaml           |  4 ++++
>  4 files changed, 21 insertions(+), 3 deletions(-)
> 
> diff --git a/include/libcamera/internal/bayer_format.h b/include/libcamera/internal/bayer_format.h
> index 5b8c1dc9..723382d4 100644
> --- a/include/libcamera/internal/bayer_format.h
> +++ b/include/libcamera/internal/bayer_format.h
> @@ -23,7 +23,8 @@ public:
>  		BGGR = 0,
>  		GBRG = 1,
>  		GRBG = 2,
> -		RGGB = 3
> +		RGGB = 3,
> +		MONO = 4
>  	};
>  
>  	enum Packing : uint16_t {
> diff --git a/src/libcamera/bayer_format.cpp b/src/libcamera/bayer_format.cpp
> index ed61202c..11355f14 100644
> --- a/src/libcamera/bayer_format.cpp
> +++ b/src/libcamera/bayer_format.cpp
> @@ -45,6 +45,8 @@ namespace libcamera {
>   * \brief G then R on the first row, B then G on the second row.
>   * \var BayerFormat::RGGB
>   * \brief R then G on the first row, G then B on the second row.
> + * \var BayerFormat::MONO
> + * \brief Monochrome image data, there is no colour filter array.
>   */
>  
>  /**
> @@ -111,6 +113,8 @@ const std::map<BayerFormat, V4L2PixelFormat, BayerFormatComparator> bayerToV4l2{
>  	{ { BayerFormat::GBRG, 16, BayerFormat::None }, V4L2PixelFormat(V4L2_PIX_FMT_SGBRG16) },
>  	{ { BayerFormat::GRBG, 16, BayerFormat::None }, V4L2PixelFormat(V4L2_PIX_FMT_SGRBG16) },
>  	{ { BayerFormat::RGGB, 16, BayerFormat::None }, V4L2PixelFormat(V4L2_PIX_FMT_SRGGB16) },
> +	{ { BayerFormat::MONO, 8, BayerFormat::None }, V4L2PixelFormat(V4L2_PIX_FMT_GREY) },
> +	{ { BayerFormat::MONO, 10, BayerFormat::CSI2Packed }, V4L2PixelFormat(V4L2_PIX_FMT_Y10P) },
>  };
>  
>  const std::unordered_map<unsigned int, BayerFormat> mbusCodeToBayer{
> @@ -146,6 +150,8 @@ const std::unordered_map<unsigned int, BayerFormat> mbusCodeToBayer{
>  	{ MEDIA_BUS_FMT_SGBRG16_1X16, { BayerFormat::GBRG, 16, BayerFormat::None } },
>  	{ MEDIA_BUS_FMT_SGRBG16_1X16, { BayerFormat::GRBG, 16, BayerFormat::None } },
>  	{ MEDIA_BUS_FMT_SRGGB16_1X16, { BayerFormat::RGGB, 16, BayerFormat::None } },
> +	{ MEDIA_BUS_FMT_Y8_1X8, { BayerFormat::MONO, 8, BayerFormat::None } },
> +	{ MEDIA_BUS_FMT_Y10_1X10, { BayerFormat::MONO, 10, BayerFormat::None } },
>  };
>  
>  } /* namespace */
> @@ -198,9 +204,10 @@ std::string BayerFormat::toString() const
>  		"BGGR",
>  		"GBRG",
>  		"GRBG",
> -		"RGGB"
> +		"RGGB",
> +		"MONO"
>  	};
> -	if (isValid() && order <= RGGB)
> +	if (isValid() && order <= MONO)
>  		result = orderStrings[order];
>  	else
>  		return "INVALID";
> @@ -280,6 +287,9 @@ BayerFormat BayerFormat::transform(Transform t) const
>  {
>  	BayerFormat result = *this;
>  
> +	if (order == MONO)
> +		return result;
> +
>  	/*
>  	 * Observe that flipping bit 0 of the Order enum performs a horizontal
>  	 * mirror on the Bayer pattern (e.g. RGGB goes to GRBG). Similarly,
> diff --git a/src/libcamera/camera_sensor.cpp b/src/libcamera/camera_sensor.cpp
> index 3e135353..fb67c15a 100644
> --- a/src/libcamera/camera_sensor.cpp
> +++ b/src/libcamera/camera_sensor.cpp
> @@ -427,6 +427,9 @@ int CameraSensor::initProperties()
>  		case BayerFormat::RGGB:
>  			cfa = properties::draft::RGGB;
>  			break;
> +		case BayerFormat::MONO:
> +			cfa = properties::draft::MONO;
> +			break;
>  		}
>  
>  		properties_.set(properties::draft::ColorFilterArrangement, cfa);
> diff --git a/src/libcamera/property_ids.yaml b/src/libcamera/property_ids.yaml
> index 104e9aaf..87be68f7 100644
> --- a/src/libcamera/property_ids.yaml
> +++ b/src/libcamera/property_ids.yaml
> @@ -706,5 +706,9 @@ controls:
>            description: |
>              Sensor is not Bayer; output has 3 16-bit values for each pixel,
>              instead of just 1 16-bit value per pixel.
> +        - name: MONO
> +          value: 5
> +          description: |
> +            Sensor is not Bayer; output consits of a single colour channel.

s/consits/consists/

Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

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